Characteristics of Integrated Air Control and Low-Pressure Exhaust Gas Recirculation Valve for Diesel Engines

摘要

The purpose of this study is to investigate the characteristics of a newly introduced integrated exhaust gas recirculation (EGR) valve. Traditionally, a exhaust-pressure regulating valve is installed to increase the EGR flow rate; the method used in this study induces an increase of the EGR flow by restricting fresh intake. Unlike the two-motor two-drive system of the low-pressure (LP)-EGR system, the air control valve (ACV) and EGR valve are constructed in a linked structure. The two valves can be controlled simultaneously by a single driver, which permits reductions in volume and weight. In order to compare the existing LP-EGR system with the integrated LP-EGR system, the characteristics of the system were analyzed by a rig test and an actual engine test. It was determined that as the EGR valve opened, the EGR rate was increased and the torque was decreased under the same load condition because of the pumping resistance caused by the ACV closing.